Clinical Characteristics and Prevalence of Breast Cancer Molecular Subtypes: A Five-Year Retrospective Study at a Tertiary Care Center in Thailand

Background: Breast cancer, the most common female cancer, has molecular subgroups that affect prognosis and treatment. Objective: To determine the prevalence, clinicopathological factors, and the molecular subtypes of breast cancer patients at Rayong Hospital. Materials and Methods: Data were collected from the medical records of Rayong Hospital regarding patients diagnosed between October 2018 and 2023. The present study covered demographics, tumor characteristics, staging, and molecular subtypes Luminal A, Luminal B, HER2-enriched, and TNBC based on ER, PR, HER2, and Ki-67. Pathological complete response (pCR) was also evaluated. Results: Seven hundred thirty-one patients were included in the study, with a mean age of 54.17 years. Most patients were diagnosed in middle age, 55.4%. Predominant molecular subtypes were Luminal B at 35.0%, Luminal A at 34.6%, TNBC at 18.4%, and HER2-enriched at 12.0%. Younger patients were shown to be correlated with TNBC subtypes, and 48.14% of the patients were diagnosed at Stage II, followed by Stages III for 27.64%. The overall pCR rate for patients receiving neoadjuvant therapy was 20%. Conclusion: Luminal B and Luminal A came out to be more predominant, whereas TNBC was associated with middle-aged patients. Most cases are diagnosed in the later stage, therefore, there is a need for early detection. Improved treatment with indications according to the individual and better screening will be necessary to better the outcomes of breast cancer.